“…One method is ashing at high temperatures to remove a large amount of fat and protein, then the ash is dissolved in concentrated nitric acid, but this method takes a long time. Thus, generally, other methods are used, such as ion exchange resin for the enrichment of radioactive elements, cation exchange resin, such as DOWEX 50W-X8 [ 39 , 40 ], anion exchange resin, such as DOWEX 1-X8 [ 39 , 41 ]. In addition to the above two methods, microwave digestion can also be used.…”